Furnace for steam-boilers



(No Model.) 1 Sh eets8heet 1f W. KENT. FURNACE FOR STEAM BOILERS. N0. 604,158. Patented May 17,1898.

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w KENT FURNACE FOR STEAM BOILERS.

Patented May 17, 1898.

lNVENTOR wdlzanvl snt' WITNESSES:

ATTORNEY (No Model.) 4 Sheets-Sheet 3.

W. KENT. FURNACE FOR STEAM BOILERS. N0. 604,158. Patented May 17, 189 8.

WITNESSES:

(No Model.) 4 Sheets-Sheet 4.

KENT. FURNACE FOR STEAM BOILERS. No. 604,158. Patented May 17,1898.

:VHII'HI ili l l' ln WILLIAM KENT, OF PASSAIC, NEW JERSEY.

FURNACE FOR STEAM-BOILERS.

SPECIFICATION forming part of Letters Patent No. 604,158, dated May 17, 1898. Application filed July 15, 1897. Serial No. 644,687. (No model.)

To all whom it may concern.-

Be it known that I, WILLIAM KENT, a citizen of the United States, residing at Passaic, in the county of Passaic and State of New J ersey, have invented certain new and useful Improvements in Furnaces for Steam-B oilers;

and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

My invention relates to certain new and useful improvements in furnaces for steam-boilers, but especially for boilers of the watertube type, and to furnaces which use bituminous coal, lignite, peat, wood, tanbark, or other fuel which contains large quantities of tarry or gaseous matter and which in burning distils a large amount of combustible gases.

The object of this invention is to so construct and arrange the furnace that all of said gases will be consumed and the heat generated thereby utilized to the best advantage in the generation of steam; and with these ends in view my invention consists in the details of construction and combination of elements hereinafter fully and in detail explained, and then specifically designated by the claims.

In order that those skilled in the art to which my invent-ion appertains may more fully understand its construction and adaptation, I will proceed to describe the same in detail, referring by letter to the accompanying drawings, forming part of this specification, in which- Figure 1 is a vertical section of my furnace as applied to a Babcock AflVilcox or other water-tube boiler, the latter being shown in side elevation. Fig. 2 is a horizontal section of the furnace, taken through the fire-door opening and over the bridge-wall at the line marked 7) b in Fig.1. Fig. 3 is a modification of Fig. 1, and Fig. 4 shows the application of the furnace to a horizontal tubular boiler.

C is a fire-chamber or oven built of brick and extending out in front of the boiler. In it the fuel is burned, either on the ordinary grate-bars or by means of a mechanical stoker or other device.

D is an ordinary bridge-wall over which the gaseous products of combustion pass on their way to the heating-surfaces of the boiler.

E E are two wing-walls built parallel to and at some distance in the rear of the bridgewall.

F is a gas mixing chamber between the bridge-wall D and the wing-walls E E.

G is a combustion-chamber into which the gases travel from the passage between the wing-walls E E.

H H are several piers, of fire-brick, projecting in front of the wall J at the rear of the combustion-chamber G.

K is a partition-wall built across the tubes of the boiler, which confines the gases ascending from the combustion-chamber G into the forward one of the three transverse gas-passages across the tubes, which passages are separated by the two partition-walls K and L is a series of flat tiles or bricks forming a deflector, laid so as to cover a portion of the forward gas-passage R and cause the gases to be deflected forward among the tubes before they escape from this forward gas-passage.

M is a series of flat tiles which form a roof to the gas-mixing chamber F and prevent the gases from passing directly from the chamber F into the forward gas-passage R.

In the operation of this furnace with ordinary grates and with bituminous coal or other gaseous fuel the alternate method of feeding coal is preferredtl1at is, the fresh coal is spread alternately on the right and left sides of the grate, an interval of some minutes of time elapsing between the feeding on the right and on the left sides. Immediately after fresh coal is put on one side of the furnace dense smoky gases arise from it, which in the ordinary boiler-setting would pass out of the chimney unburned, since in the ordinary setting there is no means provided for mixing with them an abundant supply of highly-heated air; but in this furnace suchair is supplied through the bed of partially-burned and very hot coal and coke on the other side of the grate. The two currents, one of cool smoky gas arising from the fresh coal on one side of the grate and the other of clear and very hot gas containing a large excess of air, pass together over the bridge-wall D and are com pelled by the wing-walls E E to change their direction and to mix together in the chamber F and in the contracted vertical passage between the wing-walls. The combustion of the unburned gas is further rendered more certain and complete by passing through the large combustion-chamber G, whose walls, together with the fire-brick piers H, are in a highly-heated state and perform the fun ctions of a regenerative furnacethat is, they absorb heat from the burned gases at such times as they are most intensely heated and radiate or give up heat at such times as the gases are not so hot, as during the first minute after feeding fresh coal, when there is a great excess of freshly-distilled and rather cool gases.

By the means above described complete combustion of the smoky gases is secured in the chamber G when reasonable care is used by the fireman, and the resulting thoroughlyburned products of combustion are then in the right condition to be allowed to traverse the gas-passages R, S, and T through the tubes and give up their heat to the boiler.

When automatic or mechanical stokers are used of the type which causes the coal to gradually move from the front of the furnace to the rear, dense smoky gas arises from the front portion and clear hot gas with an excess of air from the rear portion. In the ordinary setting of a water-tube boiler when such stokers are used the two currents, one of smoky and the other of clear gas, pass directly upward into the gas-passage through the tubes and do not become mixed until they have been cooled by the heating-surfaces of the boiler below the temperature of ignition. In my furnace the provision of the furnace C at a considerable distance from the heating-surface, the chambers F and G, and the wingwalls E E insures the thorough mixing of the gases and their complete combustion. My furnace is therefore peculiarly adapted to be used in connection with such mechanical stokers. Y

I have discovered by experiment that with furnaces constructed of an oven G, win g-Walls E E, and chambers F and G, set not projecting in front of the boiler, as herein shown, but underneath it, the chamber G being unprovided with the rear Wall J, but instead with a roof extending along the tubes to within a short distance of their rear end, and the gases, instead of crossing the tubes through the transverse gas-passages, traveling along them in a passage parallel to the tubes, such passage being roofed over by tiles placed on top of the upper row of tubes from their rear ends to within a short distance of their front ends, or, in other words, with furnaces constructed as-shown in Fig. 4 of United States Letters Patent No 320,563, granted to me on June 23, 1885, while the gases were completely burned and smoke was thereby prevented the longitudinal travel of the burned gases through the passage parallel with and inolosing the Water-tubes was notwell adapted to causing the water-tubes to absorb the heat from the gases, and in consequence the gases escaped into the chimney at a higher temperature than was consistent with economy of fuel. The reason of this is that on account of the well-known tendency of hot gases to ascend the gases arising from the combustionchamber into the longitudinal passage rise to the upper portion of such passage and travel along such upper portion instead of distributing themselves uniformly over the whole cross-sectional area of the passage. The tubes in the lower portion of the passage are thus rendered of no service in absorbing heat. I have not been able to overcome this difficulty by putting baffle plates or walls in the longitudinal gas-passage, since these baffle-plates causeeddies in the current of gas, in which eddies the heating-surface remains inclosed in cool gas and is thus ineffective. In my present invention I avoid this difficulty of a portion of the heating-surfaces being made ineffective by means of using, in connection with the oven 0, the chambers F and G, the wing-Walls E E, and the transverse passages R, S, and T in Fig. 1 or R and S in Fig. 3. The transverse passages compel the gases to travel uniformly over the whole of the heating-surface, and thus give up to it the greatest portion of the heat which they contain.

Fig. 3 shows a modification of the construction shown in Fig. 1. In it I have taken advantage of the tendency of hot gases to rise or remain at the top of a chamber while the cooler gases descend. In order to avoid any tendency of the ascending gases in the passage R to short-circuit or to take a portion of the passage instead of the whole of it, leaving the heating-surfaces in the neglected portion ineffective, I make the passage B, Fig. 3, of more contracted area than R, Fig. 1, and also of smaller area than the descending passage S by moving the partition-wall K forward. I then dispense with the partitionwalls and 0, Fig. 1, and make one large descending passage S, Fig. 3, and place the exit-flue and damper underneath the boiler, as shown at Q and U, Fig. 3, instead of at the end of the boiler, as at P, Fig. 1. The hot gases, after passing through the ascending passage R, Fig. 3, into the large chamber above the downward passage S, have a tendency, since they are still hot, to rise to the upper portion of this chamber. This tendency is opposed by the force of the draft, by which they are forced to pass downward to the exit-flue Q; but the continued tendency of the hot gases to rise causes them to distribute themselves and flow evenly over the whole of the wide descending passage S and not to short-circuit to the draft-opening U and leave portions of the heating-surface ineffective. The making of the ascending passage R of smaller horizontal sectional area than the descending passage S is novel and is opposed to the usual practice.

It is evident that the furnace may be applied to other forms of boiler than the water-tube boiler, and Fig. 4 shows howit may be applied to a horizontal tubular boiler. The front end of the boiler is supported in a circular opening in the upper portion of the wall J, and thechamber G is roofed over in such a manner as to cause the gases of combustion to pass into the tubes of the boiler. The furnace may also be applied to a vertical tubular boiler by resting it on the four inclosing walls of the chamber G--that is, the walls E and J and the two side walls of the setting-the upper portion of these walls being so shaped as to form a circular opening beneath the bottom tube-sheet of the boiler.

Having thus described my invention, what I claim as new, and desire to secure by Letters Patent, is

1. A furnace for a steam-boiler comprising the furnace-chamber 0 built exterior to the boiler, the wing-Walls E, E, the projecting piers H, the rear wall J,the mixing-chamber F,

' and the combustion-chamber G,substantially ing passages leading away from said chamber, all substantially as described.

3. In a steam-boiler furnace, the fire-chamber, the combustion-chamber connected thereto as described and provided with wing-walls at its sides by which the gases in passing backward are deflected toward the central part of the chamber, said combustion-chamber also having fire-brick piers serving as radiators, and passages leading from said combustion-chamber to water-containing parts of the boiler, all substantially as described.

4. In a furnace for a water-tube steamboiler, said boiler having inclined tubes and transverse gas-passages, a fire-chamber in front of the boiler, a gas-mixing chamber in rear of the fire-chamber,the fire-chamber and the mixing-chamber both having a tile orfirebrick roof to prevent the direct access of the gases to the tubes of the boiler, wing-Walls in the rear of the mixing-chamber, an open-top combustion-chamber in the rear of the mixing-chamber and partly separated therefrom by said wing-walls, through which open top the gases pass directly into the first or forward ascending transverse gas passage leading across the tubes of the boiler, in combination substantially as described.

In testimony whereof I affix my signature in presence of two witnesses.

WILLIAM'KENT.

Witnesses:

F. W. SMITH, J r., M. T. LONGDEN. 

